Question

I am using OpenMap and have to load very large dimensioned images.
I tried to load these images as big raster which fails with an OufOfMemoryException. In debug mode the layer constructor tells me that the image dimensions are too large.

In an OpenMap mailing list I found the MyJAIPlugin, which allows me to load and display GeoTiff files.

How can I show a 300mb GeoTiff in OpenMap?

Answer 1

I had a nearly same situation by loading hd maps with at least 690mb filesize.

I also used the JAIPlugIn from the mailing list and internaly they use the OMScalingRaster witch works with a BufferedImage. These limits your image size and causes the debug message.

I’ve solved it by modifieing the OMScalingRaster. I’ve changed the BufferedImage to a TiledImage to handle large images and fixed the upcoming errors. Here it’s important you change the scaleTo(Projection thisProj)-method, to scale with JAI.

Now i can load the file and it’s rendered on the map. But if you are zooming out too much, it will throw a OutOfMemoryException because in my modification i make a subimage of the part of the image that will be visible and give it as BufferedImage to the OMRaster.

Here is the mod. at the end of the scaleTo-method:

            // Now we can grab the bit we want out of the source
            // and
            // scale it to fit the intersection.

            // Calc width adjustment
            float widthAdj = (float) ((double) iRect.width
                    / (double) clipRect.width);
            // Calc height adjustment
            float heightAdj = (float) ((double) iRect.height
                    / (double) clipRect.height);

            // Create the transform
            // JAI-Version
            ParameterBlock pb = new ParameterBlock();
            pb.addSource(sourceImage.getSubImage(clipRect.x,
                    clipRect.y,
                    clipRect.width,
                    clipRect.height).getAsBufferedImage());
            pb.add(widthAdj);          // The xScale
            pb.add(heightAdj);          // The yScale
            pb.add(0.0F);           // The x translation
            pb.add(0.0F);           // The y translation
            RenderedOp newImage = JAI.create("scale",pb, null);

            bitmap = newImage.getAsBufferedImage();


            point1.setLocation(iRect.x, iRect.y);
            // setVisible(currentVisibility);
        }
    } else {
        bitmap = null;
    }
}

For the other errors by replacing BufferedImage with TiledImage use the equivalent TiledImage-methods. But to save memory you should use the TiledImage-constructor with the sharedDataBuffer flag = true.

For Exsample this mod. can handle maps (compressed 690mb) with a scaling of 1:50000 and i can zoom out to 1:600000 before the layer says it run out of memory.